GMS81C2012/GMS81C2020
HYUNDAI MicroElectronics
983501 INC
!0135H
;A ←ROM[135H]
35H
data
DB
➋
135H
data
data Æ A
~
~
~
➌
~
36H Æ X
➊
➋
~
~
~
~
data+1 → data
0F100H
0F101H
0F102H
98
35
01
➊
address: 0135
X indexed direct page (8 bit offset) → dp+X
(5) Indexed Addressing
This address value is the second byte (Operand) of com-
mand plus the data of ꢀ-register. And it assigns the mem-
ory in Direct page.
X indexed direct page (no offset) → {X}
In this mode, a address is specified by the X register.
ADC, AND, CMP, EOR, LDA, OR, SBC, STA, XMA
Example; X=15H, G=1
ADC, AND, CMP, EOR, LDA, LDY, OR, SBC, STA
STY, XMA, ASL, DEC, INC, LSR, ROL, ROR
Example; G=0, X=0F5H
C645
LDA
45H+X
D4
LDA
{X}
;ACC←RAM[X].
115H
3AH
data
data
➋
➌
data → A
~
~
~
~
~
~
data → A
➋
~
~
➊
0E550H
0E551H
C6
45
➊
D4
0E550H
45H+0F5H=13AH
X indexed direct page, auto increment→ {X}+
Y indexed direct page (8 bit offset) → dp+Y
In this mode, a address is specified within direct page by
the X register and the content of X is increased by 1.
This address value is the second byte (Operand) of com-
mand plus the data of Y-register, which assigns Memory in
Direct page.
LDA, STA
Example; G=0, X=35H
This is same with above (2). Use Y register instead of X.
DB
LDA
{X}+
Y indexed absolute → !abs+Y
Sets the value of 16-bit absolute address plus Y-register
data as Memory.This addressing mode can specify memo-
ry in whole area.
Example; Y=55H
36
MAR. 2000 Ver 1.00
HYNIX [ HYNIX SEMICONDUCTOR ]
